A GOVERNOR FOR TELEPHOXE DIALS 



1271 



weights about their pivots continues until the friction studs touch the 

 case. At this instant governing begins, and controls the dial speed until 

 the end of run-down. The speed attained by the governor will be de- 

 pendent on the friction between the studs and case, the magnitude of the 

 driving torque, and the tension to which the spring of the governor is 

 adjusted. 



In the schematic of the new governor, Fig. 4, the driving force is desig- 

 nated as F. By applying this dri^'ing force between the weight pi\-ot and 

 the center of the go\'ernor, the mechanism behaves during operation as 

 a true friction-centrifugal governor and also as a brake. This configura- 

 tion results in a gain in the ability of the governor to resist the increase 

 in speed which normally results from an increase in the applied rotational 

 force. The drive-bar force, f, and the torque produced by the stud-to-case 

 force about the pivot assists the centrifugal force in pressing the friction 

 studs against the case. 



WEIGHT 



FRICTION DRUM 



SPRING 



DRIVE BAR 



GOVERNOR 

 CASE 



Fig. 3 — The 7-type dial drive-bar governor. 



